PRIMECLUSTER Installation and Administration Guide 4.2 (Linux)

A.6.1 CF Configuration

To enable the resource database, you must change the default value of the Linux(R) kernel parameter.

The kernel parameters can be configured with the sysctl (8) utility when they are executed. The procedures for changing the kernel parameters and setting up a new kernel parameter are explained below.

The value of SHMMAX can be changed as follows:

• Edit the /etc/sysctl.conf file.

• Add the following entry. kernel.shmmax =value

Change the semaphore parameter values as follows:

kernel.sem = value1 value2 value3 value4

Define the original values as follows:

value1 = value of SEMMSL

value2 = value to SEMMNS

value3 = value of SEMOPM

value4 = value of SEMMNI

As the resource manager does not use SEMMSL or SEMOPM, you do not need to change these values. If you execute the following commands, the original parameter values will be displayed.

#sysctl -a | grep sem

#sysctl -a | grep shm

If you execute the following command, each parameter will be changed.

#sysctl -p filename (the default value of filename is /etc/sysctl.conf)

This command enables the value of /etc/sysctl.conf for the kernel. You do not have to reconfigure the kernel.
To change the kernel parameter while the OS is running, use sysctl (8). For details on the operation of sysctl, see the manual pages describing sysctl (8).

Kernel parameter	Minimum value	Comments (parameter description)
kernel.semmni	20	Value required for resource database
kernel.semmns	90	Value required for resource database
kernel.shmmax	1048576+ Value required for the resource database *	Value required for resource database
kernel.shmmni	30	Value required for resource database

*

Estimate the value required for resource database according to the following equation:

Value required for resource database = 2776 x number of resources

Estimate the number of resources according to the following equation:

Number of resources = Number of disks in shared system devices x (number of shared nodes +1) x 2

Specify the following in "Number of disks in shared system devices":

• For a disk array unit, specify the number of logical units (LUN).

• For other than a disk array unit, specify the number of physical units.

Specify the number of nodes connected to the shared disk in "number of shared nodes."

For system expansion, if you increase the logical disks, you need to re-estimate the resources and restart each node in the cluster system. If you add disks to the cluster after installation, you must then calculate the resources required for the total number of logical disks after addition.